# Airworthiness Directives; Eurocopter Deutschland GmbH Model EC135 P1 and T1 Helicopters
> **Rule** · Final rule; request for comments. · Published 1999-12-02 · Effective 1999-12-17 · 64 FR 67471
## Document
- **Document number:** 99-30623
- **Category:** airworthiness
- **Manufacturer:** Eurocopter Deutschland GmbH Model EC135 P1 and T1
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 64 FR 67471
- **Publication date:** 1999-12-02
- **Effective date:** 1999-12-17
- **FAA docket:** Docket No. 99-SW-59-AD
## Abstract

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 99-22-01, which was sent previously to all known U.S. owners and operators of Eurocopter Deutschland GmbH (ECD) Model EC135 P1 and T1 helicopters by individual letters. This AD requires, before further flight and at specified time intervals until a modified tail boom connecting frame flange (frame flange) is installed, inspecting and replacing, if necessary, the frame flange. This AD also requires, within 7 days, installing an additional bearing support on the frame flange. Thereafter, this AD requires visually inspecting the frame flange for cracks or misalignment of the slippage marks at specified time intervals. This amendment is prompted by the discovery of a crack in the frame flange at the attachment points of the tail rotor drive shaft bearing support. The actions specified by this AD are intended to prevent a fracture of the bearing frame flange, failure of the tail rotor drive shaft, and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/12/02/99-30623/airworthiness-directives-eurocopter-deutschland-gmbh-model-ec135-p1-and-t1-helicopters)
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